1. Field
The following description relates to a method and an apparatus for monitoring battery state based on an acceleration sensor signal received from an acceleration sensor.
2. Description of Related Art
With the recent increase in demand for electric and hybrid vehicles, researches are underway to develop a battery technology that may serve as a core power-supplying element of electric vehicles or hybrid vehicles. As a result, chargeable high-power secondary batteries have been developed for use in electric and hybrid vehicles. For example, lithium-ion batteries may be used as core power-supplying components of electric vehicles due to their high energy density.
A secondary battery includes a cathode active material, an anode active material, a separation membrane for separating the active materials, an electrolyte, and terminals connecting an electrode assembly and connected through a lead tab. A lithium ion may move along portions connected through the lead tab.
However, a connecting portion that connects the electronic assembly to the lead tab may be damaged due to external vibrations or physical impacts that may occur to the battery. When the battery is poorly connected to the electronic assembly due to the deterioration of the connecting portion, a performance of the secondary battery may correspondingly deteriorate, and the connecting portion may act as a resistor to generate heat. The heat generated from the connecting portion may diffuse into the secondary battery and may increase an internal temperature of the battery, decomposing the separation membrane and the electrolyte disposed therein. Due to the thermal runaway of the battery, an explosion or a fire may occur. In the event such a thermal runaway occurs in a battery for an electric vehicle while the electric vehicle is on a road, a traffic accident inviting vast human and physical damage may result.
Research has been conducted on a vibration reducing device to reduce a risk of vibrations in a high-capacity battery system for an electric vehicle. However, such a device may be used to only prevent an accident by estimating a degree of degradation of a battery due to the vibrations or by estimating the length of time it will take the battery to breakdown or get exhausted. Based on the current design of electric vehicles, batteries are constantly subjected to vibrations based on road conditions or other environmental factors. Further, batteries may be subjected to a great impact due to a situation encountered by an electric vehicle, such as a car accident. However, increasing the performance of such a protective device in order to eliminate or reduce impacts imposed on batteries while electric vehicles are driven may be difficult and may substantially increase the production cost of electric vehicles.